Lipid-based materials, such as liposomes, are used as biological carriers for pharmaceutical and other biological applications, e.g., to introduce agents into cultured cell lines. Lipids are commonly used to deliver nucleic acids to cells in vitro under low-serum or serum-free conditions, for instance in transfection. However, serum components inhibit the activity of many lipids, limiting their use in the presence of serum, both in vitro and in vivo.
Improved lipid delivery systems, e.g., to achieve higher levels of transfection both in vitro and in vivo, are desirable. In particular, lipid delivery systems that are active in the presence of serum are needed. Improved levels of transfection will allow the treatment of disease states for which higher levels of expression than are currently achievable with lipid delivery systems are needed for therapeutic effect. Alternatively, higher transfection levels will allow for use of smaller amounts of material to achieve comparable expression levels, thereby decreasing potential toxicities and decreasing cost.
There is a need for novel lipids, lipid-like materials, and lipid-based delivery systems in the art.